Multi-process descrambler

ABSTRACT

A descrambler integrated circuit (IC) is adapted to receive scrambled digital content and to descramble the scrambled digital content. According to one embodiment of the invention, the descrambler comprises a first process block, a second process block and a descrambler. The first process block is configured to encrypt a message using a unique, one-time programmable key to produce a first key. The second process block is configured to receive an encrypted second key and, using the first key, to decrypt the encrypted second key in order to recover the second key in a non-encrypted format. The descrambler is configured to descramble the scrambled digital content using the second key in the non-encrypted format and to produce digital content in a clear format.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 10/388,002filed Mar. 12, 2003, which claims the benefit of priority on U.S.Provisional Application No. 60/424,381 filed on Nov. 5, 2002.

BACKGROUND

1. Field

Embodiments of the invention relate to digital devices. Morespecifically, one embodiment of the invention relates to a system,apparatus and method for descrambling digital content in digital devicessuch as set-top boxes.

2. General Background

Analog communication systems are rapidly giving way to their digitalcounterparts. Digital television is currently scheduled to be availablenationally. High-definition television (HDTV) broadcasts have alreadybegun in most major cities on a limited basis. Similarly, the explosivegrowth of the Internet and the World Wide Web have resulted in acorrelative growth in the increase of downloadable audio-visual files,such as MP3-formatted audio files, as well as other content.

Simultaneously with, and in part due to this rapid move to digitalcommunications system, there have been significant advances in digitalrecording devices. Digital versatile disk (DVD) recorders, digital VHSvideo cassette recorders (D-VHS VCR), CD-ROM recorders (e.g., CD-R andCD-RW), MP3 recording devices, and hard disk-based recording units arebut merely representative of the digital recording devices that arecapable of producing high quality recordings and copies thereof, withoutthe generational degradation (i.e., increased degradation betweensuccessive copies) known in the analog counterparts. The combination ofmovement towards digital communication systems and digital recordingdevices poses a concern to content providers such as the motion pictureand music industries, who are reluctant in providing downloadabledigital content due to fears of unauthorized and uncontrolled copyingsuch digital content.

In response, there is a movement to require service providers, such asterrestrial broadcast, cable and direct broadcast satellite (DBS)companies, and companies having Internet sites which providedownloadable content, to introduce copy protection schemes. These copyprotection schemes may extend beyond the role of conditional access(CA), merely descrambling content to a CA-clear format for real-timeviewing and/or listening, and now include constraints and conditions onthe recording and playback. For example, currently, copying of scrambledcontent for subsequent descrambling and viewing or listening may bepermitted with the appropriate service/content provider authorization orkey provided to the digital device.

Traditional CA systems for Pay-TV originated from one-way broadcastsystems where a back channel was not available. A cryptographicprocessor, such as a smart card, in a conditional access unit, such as aset-top box, is generally infused with information and functionality inorder to automatically grant access to programs. For example, a smartcard with a Pay-TV access control application is adapted to receivemessages that grant certain service entitlements. If the set-top box wasallowed to view IPPV programs, then credit and cost limit informationwas transmitted as well. Likewise, when tuning to a program, the smartcard received messages that described which entitlements the smart cardneeded in order to grant access to the program.

Currently, hackers have manipulated both types of messages in order toview programs without paying the requisite subscription fees. Not onlycan these messages be manipulated, but the hardware can be attacked aswell. For instance, descrambling keys in the clear that are used todescramble scrambled content can be copied and sent to other set-topboxes over the Internet. Such hacking is costly to both serviceproviders as well as the content owners.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and notby way of limitation in the accompanying drawings, in which likereferences indicate similar elements and in which:

FIG. 1 is an exemplary embodiment of an content delivery systemincluding a digital device;

FIG. 2 is a first exemplary embodiment of a secure content deliverysystem that comprises the conditional access unit adapted to operatewith a smart card;

FIG. 3 is an exemplary embodiment of a method for securely transferringdescrambling keys from the smart card to the conditional access unit ofFIG. 2;

FIG. 4 is a second exemplary embodiment of a secure content deliverysystem that comprises a decoder adapted to a headend via a networkconnection;

FIG. 5 is a more detailed illustration of the decoder adapted to theheadend of FIG. 4;

FIG. 6A is a third exemplary embodiment of a secure content deliverysystem;

FIG. 6B is an exemplary embodiment of a data structure forming themating key generator transmitted through a secure content deliverysystem;

FIG. 6C is an exemplary embodiment of an entitlement management message(EMM) routed to a set-top box of the system of FIG. 6A;

FIG. 7 is a first exemplary embodiment of a descrambler IC implementedwithin the decoder of the set-top box of the system of FIG. 6A;

FIG. 8 is a fourth exemplary embodiment of a secure content deliverysystem;

FIG. 9A is a fifth exemplary embodiment of a secure content deliverysystem;

FIG. 9B is an exemplary embodiment of an entitlement management message(EMM) routed to a set-top box of the system of FIG. 9A;

FIG. 9C is an exemplary embodiment of meta-data associated with anelectronic program guide (EPG) routed to the set-top box of the systemof FIG. 9A;

FIG. 10 is a first exemplary embodiment of the descrambler ICimplemented within the set-top box of FIG. 9A;

FIG. 11 is a portion of a sixth exemplary embodiment of a secure contentdelivery system;

FIG. 12 is an exemplary embodiment of a portion of a seventh exemplaryembodiment of a secure content delivery system in which the digitaldevice is adapted with copy protection functionality;

FIG. 13 is an exemplary embodiment of the decoder implemented within thedigital device of FIG. 12; and

FIG. 14 is an exemplary embodiment of a data structure forming the copyprotection key generator of FIG. 12.

DETAILED DESCRIPTION

Various embodiments of the invention relate to an apparatus, system andmethod for protecting the transfer of data. In one embodiment, suchprotection involves the descrambling and/or decrypting of digitalcontent from one or more service providers within the digital devicesthemselves. Examples of a “service provider” include, but are notlimited to a terrestrial broadcaster, cable operator, direct broadcastsatellite (DBS) company, a company providing content for download viathe Internet, or any similar sources of content.

In the following description, certain terminology is used to describefeatures of the invention. For instance, the terms “component” or“logic” are each representative of hardware and/or software configuredto perform one or more functions. Examples of “hardware” include, butare not limited or restricted to an integrated circuit such as aprocessor (e.g., microprocessor, application specific integratedcircuit, a digital signal processor, a microcontroller, etc.), finitestate machine, combinatorial logic or the like. The term “process block”represents hardware and/or software having a dedicated function, such asa finite state machine for example.

An example of “software” includes a series of executable instructions inthe form of an application, an applet, or even a routine. The softwaremay be stored in any type of machine readable medium such as aprogrammable electronic circuit, a semiconductor memory device such asvolatile memory (e.g., random access memory, etc.) and/or non-volatilememory (e.g., any type of read-only memory “ROM”, flash memory), afloppy diskette, an optical disk (e.g., compact disk or digital videodisc “DVD”), a hard drive disk, tape, or the like.

Referring to FIG. 1, an exemplary embodiment of a content deliverysystem 100 is shown. Content delivery system 100 includes a digitaldevice 110 that receives information including program data from one ormore service providers. The program data may be propagated as a digitalbit stream for example. Digital device 110 may operate as any number ofproducts such as a set-top box or one or more components integrated intoa television, computer, audio-playback device (e.g., digital radio),audio-recording device (e.g., MP3 player), video-recording device (e.g.,digital recorder), or the like.

For instance, digital device 110 may be configured in accordance with anembedded architecture, a split security architecture, or an externalsecurity architecture. As an embedded architecture, in one embodiment,digital device 110 is implemented as a set-top box that comprises fixed,internal circuitry supporting both entitlement management anddescrambling operations.

Alternatively, in accordance with a split security architectureembodiment, digital device 110 may be adapted to receive a removablesmart card that handles entitlement management, while descrambling ofdigital content is controlled by internal circuitry.

Yet, in accordance with an external security embodiment, digital device110 may be a “point-of-deployment” product with a network card handlingboth entitlement management and descrambling operations by sending andreceiving messages over an Out-of-Band channel. Of course, externalsecurity type may also be split so that the network card handlesdescrambling operations, but adapted to communicate with a smart cardfor handling entitlement management. These and other embodiments ofdigital device 110 may be implemented while still falling within thespirit and scope of the invention.

Digital device 110 comprises a receiver 111, which processes theincoming information, extracts the program data inclusive of the digitalcontent therefrom, and provides the digital content in a perceivableformat (e.g., viewable and/or audible). The “program data” comprises anyor all of the following: system information, entitlement controlmessage(s), entitlement management message(s), or digital content. The“digital content” in the program data stream may include an image,audio, video or any combination thereof. The content may be in ascrambled or clear format.

Herein, “system information” may include information on program names,time of broadcast, source, and a method of retrieval and decoding, andwell as copy management commands that provide digital receivers andother devices with information that will control how and when thedigital content may be replayed, retransmitted and/or recorded. Thesecopy management commands may also be transmitted along with anentitlement control message (ECM), which is generally used to regulateaccess to a particular channel or service. An “Entitlement ManagementMessage” (EMM) may be used to deliver entitlements (sometimes referredto as “privileges”) to digital receiver 111. Examples of certainentitlements may include, but are not limited to access rights ordescrambling keys. A descrambling key is generally a code that isrequired by descrambler logic to recover data in the clear from ascrambled format based on the entitlements granted.

As shown, when implemented as a set-top box, digital device 110 may becoupled to other components in content delivery system 100 via atransmission medium 120. The transmission medium 120 operates totransmit program data between digital device 110 and other components incontent delivery system 100. The transmission medium 120 may include,but is not limited to electrical wires, optical fiber, cable, a wirelesslink established by wireless signaling circuitry, or the like.

Depending on the type of product corresponding to the digital device110, content delivery system 100 may include an audio system 130 coupledto the transmission medium 120. A digital VCR 140, such as a D-VHS VCR,may also be coupled to the digital device 110 and other components ofthe content delivery system 100 through the transmission medium 120.

A hard disk recording unit 150 may also be coupled to digital device 110and other components via transmission medium 120. Display 160 mayinclude a high definition television display, a monitor, or anotherdevice capable of processing digital video signals. Finally, a controlunit 170 may be coupled to the transmission medium 120. Control unit 170may be used to coordinate and control the operation of some or each ofthe components on content delivery system 100.

The digital content of the program data may be transmitted in scrambledform. In one embodiment, as part of the program data, accessrequirements may be transmitted along with the scrambled content todigital device 110 (e.g., set-top box) that is implemented with receiver111 thereby functioning as a conditional access unit. An “accessrequirement” is a restrictive parameter used to determine if digitaldevice 110 implemented with conditional access functionality,hereinafter referred to herein as the “conditional access unit 110,” isauthorized to descramble the scrambled content for viewing or listeningpurposes. For example, the access requirement may be a key needed toperceive (view and/or listen to) the content, a service tag associatedwith a given service provider, or even a particular descramblingsoftware code.

When a scrambled program is received by conditional access unit 110, theaccess requirements for the program are compared to the entitlementsthat the conditional access unit 110 actually has. In order for theconditional access unit 110 to display the scrambled content in clearform, in one embodiment, the access requirements associated with thedigital content are compared to the entitlements of the conditionalaccess unit 110. The entitlements may state that conditional access unit110 is entitled to view/playback content from a given content providersuch as Home Box Office (HBO), for example. The entitlements may alsoinclude one or more keys needed to descramble the digital content. Theentitlements also may define the time periods for which conditionalaccess unit 110 may descramble the digital content.

Thus, in one embodiment, access requirements and entitlements form apart of the access control system to determine whether a conditionalaccess unit or even a decoder is authorized to view a particularprogram. It is contemplated that the description below focuses onmechanisms to recover audio/visual content such as televisionbroadcasts, purchased movies and the like. However, it is contemplatedthat the invention is also applicable to the descrambling of audiblecontent only (e.g., digitized music files).

The access requirements and entitlements can provide consumers with avariety of choices for paying for the content and gaining access to thescrambled content. These choices may include pay per play (PPP), pay perview (PPV), impulse pay per view (IPPV), time based historical, pay pertime (PPT). “Impulse pay per view” is a feature which allows purchase ofPPV movies through credit that has been previously downloaded into theset-top box. Purchase records may be stored and forwarded by phone to abilling center. “Time based historical” allows access to content thatwas delivered during a past time period, such as March through December,1997, for example. The access requirements and entitlements can alsoprovide consumers with different options for storing the scrambledcontent.

The access requirements may be delivered to the conditional access unit,located within digital device 110 or coupled thereto over transmissionmedium 120, using packet identifiers (PIDs). Each PID may contain theaccess requirements associated with a given service. The content that isdelivered to the conditional access unit may also include a large numberof PIDs, thus enabling special revenue features, technical features, orother special features to be performed locally.

Before receiving the content, the customer may be given a number ofchoices for gaining access to the digital content that is going to bestored to media. The customer may be required to purchase the right toaccess and view the content. Therefore, if the customer wants to recordthe content for later retrieval and viewing, the access requirementsthat the customer bought also need to be stored with the digitalcontent.

In addition, there may be copy-protection applied to the descrambleddigital content (e.g., transport stream) as shown in FIGS. 12 and 13.Copy-protected digital content will be re-scrambled across an interfaceinterconnecting a destination interface and a source. The source anddestination interface need to agree on the key used to re-encrypt thiscontent. This copy protection key can be encrypted with the unique keyassociated with the digital device. The unique key can be receivedthrough an EMM or other method, e.g. factory load procedure.

As seen in FIG. 2, a first exemplary embodiment of a secure contentdelivery system that comprises a conditional access unit 201 adapted tooperate with a smart card interface 220 is shown. This embodiment isconsistent with a split security architecture and an external securityarchitecture. In a split security architecture implementation, digitaldevice 110 operates as a conditional access unit 201 (e.g., equivalentto conditional access unit 110 of FIG. 1), but is implemented as aset-top box or other type of digital device.

Although smart card interface 220 may be built into digital receiver111, it is expected that digital receiver 111 will have an expansionslot, such as a PCMCIA slot or Universal Serial Bus (USB) slot forexample, to receive a card 210 complementary to interface 220. For thisembodiment, digital receiver 111 comprises an optional processor 230 anda descrambler integrated circuit (IC) 240.

Smart card interface 220 is adapted for attachment to smart card 210,which stores one or more encrypted descrambling keys for descramblingincoming digital content. Smart card 210 transmits the descramblingkey(s) in encrypted form to smart card interface 220. In order toprotect the descrambling key(s), generally referred to as “DK,” frombeing improperly extracted by an interloper monitoring communicationsbetween smart card 210 and smart card interface 220, smart card 210 mayuse an encryption key unique to conditional access unit 201 to encryptthe DK. This allows conditional access unit 201 to decrypt the DK in asecure manner and use the DK in a clear format to descramble the digitalcontent.

More specifically, according to one embodiment of the invention, anexternal cryptographic processor 215 of smart card 210, receives the DKneeded to descramble content. A storage element 212 (e.g., volatile ornonvolatile memory) is previously loaded with one or more keys forencrypting the DK. Such loading may be performed during manufacture ofsmart card 210, during manufacture of storage element 212 or bycryptographic processor 215 when storage element 212 is on-chip.Encryption logic 214 of smart card 210 encrypts the DK with the one ormore keys that are unique to descrambler IC 240.

For this embodiment, smart card 210 delivers the encrypted DK 216 todescrambler IC 240. Herein, processor 230 receives encrypted DK 216through interface 220, although encrypted DK 216 may be sent directly todecryption logic 260. Processor 230 may be implemented to performadditional operations to counteract additional obfuscation techniquesperformed on the DK.

Decryption logic 260 of the descrambler IC 240 will decrypt the DK usingone or more unique keys stored in a storage element 250. In oneembodiment, storage element 250 comprises one or more key registersloaded at manufacturer or after implemented within conditional accessunit 201 through initial program data transmitted to conditional accessunit 201. Decryption logic 260 then writes the decrypted DK alternatelyinto ODD and EVEN key storage elements (not shown) of descrambler logic270. Descrambler logic 270 then applies the ODD/EVEN DK to the incomingscrambled content 280 at the right time and outputs descrambled programcontent 290. Of course, alternatives to the loading of ODD and EVEN keystorage elements may be utilized for descrambling of incoming scrambledcontent 280.

Thus, the transfer of the descrambling key from smart card 210 toconditional access unit 201 is secure, because the descrambling key istransferred in encrypted form. The descrambling key remains secure inconditional access unit 201 because the descrambling key is notdecrypted by non-secure processor 230. The descrambling key is onlydecrypted in descrambler IC 240 that actually uses the descrambling key,and thus, the descrambling key is never exposed in the clear, and cannotbe obtained by hackers.

Furthermore, the key used to decrypt the encrypted DK 216 is stored inhardware (e.g., storage element 250) of descrambler IC 240. Storageelement 250 cannot be hacked unless the silicon of storage element 250is probed. Furthermore, the key may only be valid for one particularconditional access unit 201, and may not be used by other units todecrypt the encrypted DK 216, because the DK is encrypted by smart card210 using a key that is unique to an associated conditional access unit201. Therefore, the transmission of the encrypted DK 216 to conditionalaccess unit 201 is secure.

Descrambler IC 240 handles the secure processing of the descramblingkeys. This descrambler IC 240 has no CPU, no firmware, and no software.There is no complicated key hierarchy. A non-processor based descramblerIC 240 receives encrypted DK 216, applies a unique key to it, anddecrypts it. No instructions, no code, and no software is loaded intodecryption logic 260. The decryption is performed entirely by decryptionlogic 260 being a hardware circuit or state machine using only a singlekey function.

One or more unique keys, generally referred to herein as “Unique Key,”may be programmed into storage element 250 during manufacture or duringimplementation within a set-top box, television, or NRSS-B module. Forexample, in one embodiment, descrambler IC 240 is implemented with aprogrammable non-volatile storage element 250 such as flash. In anotherembodiment, descrambler IC 240 is implemented with non-programmable,non-volatile memory that can be written only once in order to enhancesecurity. As a result, there is no way to either improperly read oroverwrite the Unique Key that is originally loaded into storage element250. An association between the serial number of conditional access unit201 and the Unique Key loaded into descrambler IC 240 of the conditionalaccess unit 201 may be recorded.

When conditional access unit 201 is manufactured and a smart card 210 isinstalled, smart card 210 can receive the Unique Key associated withconditional access unit 201 at the time of pairing. From then on, smartcard 210 is “paired” to that particular host (e.g., conditional accessunit 201). Later, if smart card 210 is ever replaced or moved to a newhost, smart card 210 may be adapted to receive a unique key associatedwith the new host via an Entitlement Management Message (EMM). Ofcourse, as an alternative, a new smart card with a newly programmedunique key may also be delivered to the user.

An exemplary method for transferring a descrambling key from smart card210 to conditional access unit 201 of FIG. 2 is shown in FIG. 3. Adescrambling key is encrypted in the smart card using a key stored innon-volatile memory of the smart card (block 300). This key (“UniqueKey”) stored in the smart card is associated with the key stored in thestorage element of the descrambler IC. The encrypted descrambling key isreceived from the smart card (block 310).

This method includes receiving a digital bitstream including programdata in a descrambler IC, where the program data includes systeminformation and scrambled digital content (block 320). The encrypteddescrambling key is decrypted using a key stored in a storage element ofthe descrambler IC (block 330). The scrambled digital content isdescrambled in the descrambler IC using the decrypted descrambling key(block 340), and the descrambled digital content is output (block 350).

As an alternative embodiment to the conditional access unitimplementation of FIG. 2, the smart card may be replaced by a headendserver (“headend”) 410 of a one-way or two-way network 420 as shown inFIG. 4. Headend 410 maintains the access rights for the digital deviceoperating as a decoder (referred to as “decoder 401”), instead ofmaintaining such access rights in a local cryptographic processor 215 ofsmart card 210 of FIG. 2.

Headend 410 can deliver one or more service keys (generally referred toas “Service Key”) based on the Unique Key stored in Descrambler IC 440.The encrypted Service Key may be stored locally in decoder 401 tofacilitate transitions from one channel to another. The Service Key arestored in encrypted form, and is loaded as needed into Descrambler IC440. The Service Key is decrypted within Descrambler IC 440, by usingthe Unique Key stored in a storage element 450 of Descrambler IC 440.

In one embodiment of the invention, the Service Key is used as adescrambling key to descramble the content directly. In anotherembodiment of the invention, the Service Key is used to decrypt one ormore descrambling keys, which are received in-band with the scrambledcontent and subsequently used for descrambling purposes. Each servicekey may be encrypted using different public and proprietary encryptionalgorithms. These different proprietary algorithms may be considered asanti-piracy measures to invalidate clone hardware.

Headend 410 can deliver the Service Key on a channel or “tier ofservice” basis in the EMMs. The service keys are encrypted, storedlocally in decoder 401, and used by a processor 430 as needed whentuning to different channels. While this embodiment works in one-way(non-IPPV) broadcast networks, it also performs in two-way, interactivenetworks, where the Service Key for a particular service is requested,such as IPPV or VOD purchases or any other non-subscription service. Areturn channel 421 is used to request the Service Key because theability to grant access to a new service is performed by headend 410instead of a local controlling cryptographic processor.

In order to avoid overload problems at headend 410 caused by a largenumber of simultaneous impulse buys of IPPV programs, a Free Previewperiod can be determined and IPPV programs can be marketed in advance ofthe actual viewing. In this embodiment, service keys for individualshows or movies may be requested by decoder 401 and delivered ahead oftime. For example, interactive networks, such as a cable system havingreturn channel 421 such as a DOCSIS modem or Out-of-Bandtransmitter/receiver for example, can deliver a Request for Program Key(RPK) message from decoder 401 to headend 410. Alternatively, decoder401 may request the Service Key in real-time for each program accessed.

A controller (not shown) on headend 410 processes the RPK message. TheRPK message may contain an address of decoder 401 as well as informationneeded to identify the channel to be viewed (all of which may beobtained from Motion Picture Experts Group “MPEG” system and programinformation already processed by the insecure processor). The RPKrequest may be encrypted, if desired, for non-repudiation and preventionof denial of service attacks, such as IPPV or VOD requests for example.

Upon receipt of the RPK message, headend 410 accesses entries of anaccess control list (listing each entitlement of decoder 401) andverifies decoder 401 is authorization to receive a particular ServiceKey. If authorized, headend 410 sends the Service Key (encrypted usingthe Unique Key contained in storage element 450 located in thedescrambler IC) to decoder 401.

FIG. 5 provides a more detailed illustration of decoder 401 of FIG. 4adapter to headend 410 for request and receipt of the Service Key.According to one embodiment of the invention, program data 500 such asan Entitlement Control Message (ECM) or meta-data associated with anElectronic Program Guide (EPG) is provided to decoder 401 by a serviceprovider. The program data 500 is adapted to convey at least anidentifier of the desired channel or service (referred to as “Channel orService ID”). In the event that program data 500 is an IPPV or VODprogram, program data 500 may further include a Program identifier(Program ID).

An MPEG Demultiplexer 510 operates as a message processor to extract theChannel or Service ID. The Channel or Service ID are routed to processor430, which in combination with transmitter/receiver logic 520 generatesthe RSK message 421 for routing to headend 410 over return channel 421.

In response, the requested Service Key (SK) in an encrypted format isreceived by the transmitter/receiver logic 520, which provides the SK toprocessor 430. Processor 430 may store the SK in a memory 435 and/orprovide the SK to descrambler IC 440 for descrambling incoming scrambledcontent in real-time. For instance, memory 435 is an optional componentfor use if it is desirable to storage the SK locally.

Upon receiving the scrambled content of the program data, descrambler IC440 descrambles such content, which is subsequently supplied to MPEGdecoder 530 if the content is compressed with a MPEG format. MPEGdecoder 530 decompresses the digital content and subsequently routes thedecompressed digital content to either a digital-to-analog (D/A)converter for display on a television, or a Digital Video Interface(DVI) link.

As shown, processor 430, memory 435, descrambler IC 440, MPEGDemultiplexer 510, transmitter/receiver logic 520 and MPEG decoder 530may be implemented on two or more integrated circuits interconnectedthrough bus traces or another communication scheme (e.g., wires, opticalfiber, etc.). Alternatively, these components may be implemented on asingle integrated circuit.

In this embodiment, the SK may be valid for a certain period of time.Decoder 401 may store the SK in memory 435, allowing decoder 401 tore-access the service with if SK is still valid without having torequest that Service Key again. In this embodiment, the SK is stored inencrypted form (as it comes over the network from headend 410) in memory435.

The SK may be valid for the duration of a program or it may be valid fora selected period of time, e.g. 6 hours. Using a key for a longer periodof time will reduce the overall number of transactions between decoder401 and headend 410 because, once SK is stored in memory 435 of decoder401, it is readily available. Depending on the duration of the currentService Key (e.g., SK), the next Service Key (SK_(next)) may bedelivered along with the SK. Alternatively, decoder 401 may request theSK_(next) after detecting the end of the SK's valid Epoch (e.g., timeduration of the SK). In different embodiments, the Service Key may bevalid for a duration of a user's subscription period.

Services can be sold a-la-carte or sold as a package. There may beseveral tiers of services, each identified by a Service ID. For example,there may be a basic tier of services, a medium tier offering moreservices, and advanced tiers offering different premium services. Eachincremental tier of services may be given a separate Service Key.

In summary, decoder 401 of FIG. 4 comprises a Descrambler IC 240 with aUnique Key loaded during IC manufacturer or creation of decoder. ServiceKeys are delivered to decoder 401 encrypted by the Unique Key and storedin encrypted form in decoder 401. Alternatively, decoder 401 couldrequest a Service Key each time that decoder 401 tunes to a channelwithout storing the Service Key(s} locally.

The entitlements normally held by the secure cryptographic processor ofFIG. 2 are held by the controlling authority such as a key server inheadend 410 of FIG. 4 for example. Processor 430 in decoder 401 mayreceive a message (e.g., an ECM or an EMM), which tells it what it isauthorized to descramble so that it may properly display viewing optionsto a viewer. Processor 430 can then request Service Keys for selectedchannels.

There is no embedded “secure” firmware or software. Using the hardwaredecryption circuit mentioned above, an embedded processor core orfirmware that performs a cryptographic function is not needed. Thisenables a number of conditional access applications, which may bedownloaded to the insecure processor. The Service Key is unit keyencrypted. It may be a public asymmetric key or secret symmetric key.

Additional advantages include Pay-TV applications without using acryptographic processor by providing decoder 401 having Descrambler IC440 with Unique Keys hardwired therein. Decoder 401 can request aService Key or Descrambling key from a network provider. Local accesscontrol can be performed by processor 430 because the critical “secure”function is isolated in Descrambler IC 440.

Referring now to FIG. 6A, a third exemplary embodiment of a securecontent delivery system 600 is shown. Secure content delivery system 600comprises a subscriber management system 610, a Conditional Access (CA)control system 620, a plurality of mating key servers associated withdifferent set-top box manufacturers 630 ₁-630 _(N) (N≧2) and a set-topbox 640 adapted to receive a smart card 650. Smart card 650 communicateswith a descrambler IC 660, which includes local memory 670 configured tostore a unique key (referred as “Unique Key”) 680 of set-top box 640.Unique Key 680 is loaded during IC manufacturer or creation of set-topbox 640.

Once a user of set-top box 640 desires to receive particular programdata, set-top box 640 determines whether entitlements associated withthe requested program data are already stored therein. If theentitlements are not stored, the user may be notified by a screendisplay and prompted to issue a request 611. Request 611 may be providedby the user via (i) an out-of-band communication pathway (e.g.,electronic mail over the Internet, telephone call by the user, etc.) or(ii) an in-band communication pathway to CA control system 620 incommunication with set-top box 640 as shown. Alternatively, request 611may be sent automatically or may be routed to CA control system 620which performs a lookup of information to authorize the usersubstantially in real time.

For one embodiment, request 611 is a message that comprises anidentifier (e.g., an alphanumeric, or numeric code) of the requestedcontent, a serial number of set-top box (referred to as “STB SerialNum”) and/or an identifier of smart card 650 (referred to as “Smart CardID”). Implemented as any information processing system (e.g., server,relay station or other equipment controlled by a service provider orservice provider), subscriber management system 610 processes request611 and determines what entitlements are to be provided to set-top box640. Although not shown, it is contemplated that CA control system 620could be configured to perform a lookup of databases containing serialnumbers of set-top boxes or smart card IDs, thereby eliminating accessto subscriber management system 610.

Upon receiving an authorization (AUTH) message 612 from subscribermanagement system 610, which may include the STB Serial Num and perhapsglobal keys (e.g., keys used to decrypt ECMs sent in-band with thecontent), CA control system 620 routes STB Serial Num 641 and a matingkey generator 621 to at least one of the mating key servers 630 ₁ . . ., or 630 _(N) (generally referred to as “mating key server 630 _(i),”where i≧1). CA control system 620 operates as an intermediary tocoordinate delivery of a mating key 622 that is used to recover digitalcontent from downloaded, scrambled content. CA control system 620 may beimplemented as a headend, a broadcast station, a satellite uplink or thelike.

Alternatively, instead of CA control system 620 routing mating keygenerator 621 and STB Serial Num 641 to a mating key servers 630 ₁-630_(N), it is contemplated that such information may be sent to a trustedthird party 635, which maintains and controls access to databasesfeaturing mating keys. The values associated with mating key generator621 and/or STB Serial Num 641 are used to retrieve mating key 622.“Trusted third party” 635 may include, but is not limited or restrictedto a governmental entity, a company independently managed from anymanufacturer, or the like.

Prior to transmission of STB Serial Num 641 and mating key generator621, CA control system 620 may perform an authentication scheme with aselected mating key server, such as server 630 ₁, in order to establisha session key between CA control system 620 and mating key server 630 ₁.Of course, the authentication scheme would be performed with trustedthird party 635 if implemented in lieu of mating key server 630 ₁. Thesession key can be used to encrypt information exchanged between theparties in order to provide a secure link there between. Examples ofvarious types of authentication schemes include an exchange of digitalcertificates, digital signatures, hash values or the like.

As shown in FIG. 6B, mating key generator 621 is a message thatcomprises one or more of the following: a Set-Top-Box Manufactureridentifier (STB Manufacturer ID) 623, a Service Provider ID 624, aconditional access (CA) Provider ID 625 and a Mating Key Sequence Number626. Of course, the size (in bits) of these values/fields can be varied.

For this embodiment, “STB manufacturer ID” 623 is a predetermined valuethat identifies a manufacturer of set-top box 640. Of course, it iscontemplated that STB manufacturer ID 623 is optional, depending on theparticular arrangement of STB Serial Num 641. “Service Provider ID” 624is a value (e.g., one or more bits such as 16-bits) that identifies thecommunications system provider as well as the selected distributionmechanism. For example, Service Provider ID 624 may identify whichcable, satellite, terrestrial or Internet company is supplying therequested program data and/or the particular head-end server of thatcompany. “CA Provider ID” 625 indicates the provider of CA controlsystem 620. “Mating Key Sequence Number” 626 is used for reorderingpackets of information if mating key 622 is more than one packet inlength, and in certain systems, may also be used to indicate expirationof mating key generator 621.

Referring back to FIG. 6A, STB Serial Num 641 may have a unique portionfor each STB Manufacturer ID 623 in order to identify mating key server630 ₁, . . . , or 630 _(N) (or database of trusted third party 635) towhich access is sought. Alternatively, STB Serial Num 641 may beexpanded to include a serial number of set-top box 640 as well as a codefield to identify the manufacturer of that set-top box 640. Of course,the number of bits is a design choice.

Upon receipt of mating key generator 621 and STB Serial Num 641, theappropriate mating key server (e.g., server 630 _(i), where i≧1) returnsmating key 622. In this embodiment, mating key 622 is used to encrypt adescrambling key needed to descramble scrambled content being sent toset-top box 640. More specifically, mating key server 630 _(i) accessesa pre-stored key being an identical copy of Unique Key 680 and encryptsmating key generator 621 using the accessed key. This produces a keyequivalent to mating key 622. Alternatively, it is contemplated thatmating key generator 621 may undergo a one-way hash operation in whichthe result is encrypted or only a portion of mating key generator 621may be encrypted to produce mating key 622. A similar operation needs tobe repeated, however, within descrambler IC 660.

Upon receipt of mating key 622, CA control system 620 generates anentitlement management message (EMM) 648 along with one or more ECMs 642sent to smart card 640. One embodiment of EMM 648 is illustrated in FIG.6C.

As shown in FIG. 6C, EMM 648 comprises at least two of the following:Smart Card ID 643, length field 644, mating key generator 621, “M” (M≧1)key identifiers 645 ₁-645 _(M) and keys 646 ₁-646 _(M) associated withkey identifiers 645 ₁-645 _(M), respectively. Of course, otherentitlements 647 may be included in EMM 648. Also, it is contemplatedthat mating key generator 621 may be excluded from EMM 648 and sentseparately and generally concurrent with EMM 648.

In particular, with respect to FIG. 6C, smart Card ID 643 is a bit valuethat is used to indicate a particular set-top box and perhaps themanufacturer of the set-top box. “EMM length field” 644 is a bit valuethat is used to indicate the length of EMM 648. Mating key generator621, as shown, is a bit value that includes the parameters forth abovein FIG. 6B. Each “key identifier” 645 ₁-645 _(M) is a 16-bit entitlementtag value that is signed for use in checking whether keys 646 ₁-646 _(M)have been illicitly altered. Keys 646 ₁-646 _(M) are used to decryptECMs 642 used to deliver access requirements and at least onedescrambling key in an encrypted format.

Smart card 650 receives EMM 648 and forwards mating key generator 621and an encrypted descrambling key 651 recovered from ECM 642 todescrambler IC 660 of set-top-box 640 as described in FIGS. 7A-7C.

FIG. 7A is a first exemplary embodiment of descrambler IC 660implemented within set-top box 640 of FIG. 6A. On receipt of mating keygenerator 621 and encrypted descrambling key 651 from smart card 650,descrambler IC 660 comprises a first process block 661 that performs anencryption operation on mating key generator 621 using Unique Key 680stored in descrambler IC 660. The encryption operation may be inaccordance with symmetric key cryptographic functions such as DES, AES,IDEA, 3DES and the like. The “DES” operation is shown merely forillustrative purposes.

The encryption operation on mating key generator 621 produces a key 663identical to mating key 622, which is loaded into a second process block664. Process block 664 is used to decrypt encrypted descrambling key 651to produce a descrambling key 665. Descrambling key 665 is used fordescrambling scrambled content 666 loaded into set-top box 640 and inparticular descrambler IC 660. Descrambling may include performance of3DES operations on scrambled content 666. The result is content in aclear format, which may be transmitted from descrambler IC 660 andsubsequently loaded into a MPEG decoder as shown in FIG. 5 or optionallyinto a D/A converter, or DVI Interface.

It is contemplated that process blocks 661 and 664 may be altered tosupport decryption and encryption respectively, depending on how matingkey 622 is formulated.

FIG. 7B is a second exemplary embodiment of descrambler IC 660implemented within set-top box 640 of FIG. 6A. The descrambling is inaccordance with 3DES with 2 keys. As set forth in FIG. 7A, descramblerIC 660 comprises a first process block 661 that performs an encryptionoperation on mating key generator 621 using Unique Key 680.

The encryption operation on mating key generator 621 produces key 663,which is identical to mating key 622. The key 663 is loaded into two DESprocess blocks 664 ₁ and 664 ₂. Process block 664 ₁ is used to decrypt afirst encrypted descrambling key 652 to produce a first descrambling key(DK1) 665 ₁. Process block 664 ₂ is used to decrypt a second encrypteddescrambling key 653 to produce a second descrambling key (DK2) 665 ₂.DK1 665 ₁ and DK2 665 ₂ are used by a low-level 3DES descrambling logic667 for descrambling scrambled content 666.

Of course, it is further contemplated that process block 661 may beconfigured to support 3DES with multiple keys as shown in FIG. 7C. Forthis embodiment, multiple mating key generators 621 ₁ and 621 ₂ areprovided by smart card 650 to produce two keys 663 ₁ and 663 ₂ that areprovided to process blocks 664 ₁ and 664 ₂, respectively. These processblocks 664 ₁ and 664 ₂ produce descrambling keys 665 ₁ and 665 ₂ thatare used by a low-level 3DES descrambling logic 667 for descramblingscrambled content 666.

As illustrated in FIG. 7C, a first mating key generators 621 ₁ may beconfigured as mating key generator 621 of FIG. 6B. However, a secondmating key generators 621 ₂ may be configured to authenticate copyprotection parameters placed into key 663 ₂. For instance, second matingkey generators 621 ₂ may comprise a copy control information (CCI) fieldthat provides copy controls and a content identifier field thatidentifies incoming content to which the copy controls are applied. Forinstance, the CCI field may identify that the content cannot be copiedfor persistent storage or may be copied a certain number of times (once,twice, etc.). The CCI field may be used to identify the number of timesthat the content can be played back or sets prescribed viewing times forsuch content.

The second mating key generators 621 ₂ may further comprise a Content IDfield including a value that identifies the digital content associatedtherewith and may include data to manage validity/expiration of thedigital content. The second mating key generators 621 ₂ may furthercomprise a Copy Generation Number field including a value thatidentifies the number of times the digital content can be copied. Ofcourse, to reduce the size of the fields, multiple parameters may behashed and stored in the fields.

Referring now to FIG. 8, a fourth exemplary embodiment of a securecontent delivery system 700 is shown. Secure content delivery system 700comprises subscriber management system 610, CA control system 620, amating key gateway 710, mating key servers 630 ₁-630 _(N) and set-topbox 640. In lieu of transmitting mating key generator 621 and STB SerialNum 641 from CA control system 620 to mating key servers 630 ₁-630 _(N)as shown in FIG. 6A, such information may be routed to mating keygateway 710. Mating key gateway 710 accesses the STB Manufacturer ID 623of FIG. 6B from mating key generator 621 and appropriately routes matingkey generator 621 and STB Serial Num 641 to a selected mating key server630 _(i). This reduces the amount of processing time by CA controlsystem 620 or servers 630 ₁-630 _(N) to recover mating key 622.

Alternatively, instead of mating key gateway 710 routing mating keygenerator 621 and STB Serial Num 641 to the selected mating key server630 _(i), it is contemplated that such information may be routed totrusted third party 635, which accesses a targeted database forretrieval of a mating key. The database selected for retrieval of matingkey 622 is based on values associated with mating key generator 621and/or STB Serial Num 641. For instance, each database may be accessibleover a range of addresses based on values associated within mating keygenerator 621 and/or STB Serial Num 641. These values are used toidentify the targeted database.

FIG. 9A is a fifth exemplary embodiment of a secure content deliverysystem 800. Secure content delivery system 800 comprises subscribermanagement system 610 and a CA control system 810, a plurality of matingkey servers 630 ₁-630 _(N) associated with different set-top boxmanufacturers, a set-top box 820, a mating key gateway 830 (similar togateway 710 of FIG. 8), and a network interface 840 (e.g., DOCSIS CMTS).Set-top box 820 comprises a descrambler IC 860 including local memory870 configured to store a unique key 880 (referred to as “Unique Key”)of set-top box 820. The Unique Key 880 is loaded during IC manufactureror creation of set-top box 820.

Set-top box 820 receives electronic program guide (EPG) meta-data withthe EPG in an unscrambled format and receives digital programmingcontent 850 in a scrambled format. In one embodiment, EPG meta-data 900is provided out-of-band by CA control system 810. As shown in FIG. 9C,one embodiment of EPG meta-data 900 includes multiple tag entries 910₁-910 _(s) (S≧1) for different types of content provided by a serviceprovider. Each tag entry 910 _(j)(1≦j≦S) comprises at least a channelname 920 _(j), a name of the content 930 _(j), and a key identifier 940_(j) indicating the tier of service associated with the channel. Inaddition, each tag entry 910 _(j) further comprises a program identifier(PID) 950 _(j) and a mating key generator (MKG) 960 _(j). Meta-data 900is used to provide a mating key generator (e.g., mating key generator621) and key identifier(s) for verification of the keys provided in theEMM 885.

Referring back to FIG. 9A, once a user of set-top box 820 desires toreceive particular type of content (e.g., PPV movie, broadcast channel,etc.), set-top box 820 determines whether entitlements associated withthe requested content are already stored therein. If the entitlementsare not stored, the user may be notified directly through a screendisplay or audio playback and prompted to provide a request 811 tosubscriber management system 610 (or CA control system 810).Alternatively, the request 811 may be sent automatically without usercontrol. Request 811 may be provided out-of-band (e.g., telephone callor e-mail over Internet via DOCSIS) as shown, or in-band to subscribermanagement system 610.

As shown for this embodiment, upon receiving an authentication message815 from subscriber management system 610, including STB Serial Num 831and entitlements (or looking up STB Serial Num 831 at CA control system810), CA control system 810 routes STB Serial Num 831 and mating keygenerator 832 to mating key gateway 830. Mating key gateway 830 operatesas an intermediary to coordinate delivery of mating key 833 that is usedto extract the requested content from downloaded, scrambled information.Of course, CA control system 810 may perform an authentication schemewith mating key gateway 830 in order to establish secure communicationsthere between.

Upon receipt of mating key 833, CA control system 810 generates one ormore entitlement management message (EMM) 885. No ECMs are provided;only channel keys over EMM 885 for example. One embodiment of EMM 885 isillustrated in FIG. 9B.

As shown in FIG. 9B, EMM 885 comprises at least two of the following:STB Serial Num 831, EMM length field 842, mating key generator 832, “M”(M≧1) key identifiers 844 ₁-844 _(M) and encrypted service keys 846₁-846 _(M) associated with key identifiers 844 ₁-844 _(M), respectively.Of course, other types of entitlements besides identifiers or servicekeys may be included in EMM 885 and the size (in bits) of these valuescan be varied. Also, it is contemplated that mating key generator 832may be excluded from EMM 885 and sent separately and generallyconcurrent with EMM 885.

STB Serial Num 831 is a value that is used to indicate a particularset-top box and perhaps the manufacturer of the set-top box. “EMM lengthfield” 842 is a bit value that is used to indicate the length of EMM885. Mating key generator 832, as shown, is a bit value that includesthe parameters forth above in FIG. 6B. Each “key identifier” 844 ₁-844_(M) is a 16-bit value that indicates a tier of service associated witha corresponding encrypted service key 846 ₁-846 _(M), respectively. Theencrypted service keys 846 ₁-846 _(M) are decrypted by a key producedwithin descrambler IC 860 that corresponds to mating key 833 of FIG. 9A.

FIG. 10 is a first exemplary embodiment of descrambler IC 860implemented within set-top box 820 of FIG. 9A. On receipt of mating keygenerator 832 and encrypted service keys 846 _(j) (1≦j≦M) included inEMM 885, descrambler IC 860 comprises a first process block 861 thatperforms an encryption operation on mating key generator 832 usingUnique Key 880 previously stored in descrambler IC 860. The encryptionoperation may be in accordance with symmetric key cryptographicfunctions such as DES, AES, IDEA, 3DES and the like. Of course, it iscontemplated that process block 861 may be altered to perform a hashingfunction in lieu of an encryption function.

The encryption operation on mating key generator 832 produces a key 863that is identical to mating key 833. Key 863 is loaded into a secondprocess block 864 that is used to decrypt the encrypted service key 846_(j) to recover the service key used to descramble scrambled content 850loaded into set-top box 840 and in particular the descrambler IC 860.Descrambling may include performance of 3DES operations on the scrambledcontent. The result may be content in a clear format, which istransmitted from descrambler IC 860 and subsequently loaded into a MPEGdecoder as shown in FIG. 5 or optionally into a D/A converter, or DVIInterface.

Referring now to FIG. 11, a portion of a sixth exemplary embodiment of asecure content delivery system 900 is shown. In lieu of subscribermanagement system 610 and CA control system 810 of FIG. 9A, mating keygateway 830 may be adapted for communications with a plurality ofsubscriber management systems (SMS) 910 ₁-910 _(K) (K≧1) each associatedwith a different service provider. Each of these subscriber managementsystems 910 ₁-910 _(K) supply mating key generators and STB Serial Nums920 ₁-920 _(K) to mating key gateway 830 and, in return, receivecorresponding mating keys 930 ₁-930 _(K). These mating keys 930 ₁-930_(K) are used to encrypt service keys provided to one or more targetedset-top boxes (not shown). Alternatively, trusted third party 635 may beutilized as shown in FIGS. 6A, 8 and 9A.

For example, for this illustrated embodiment, subscriber managementsystems 910 ₁ and 910 ₂ are terrestrial broadcasters, each providingmating key generators and STB Serial Nums 920 ₁, 920 ₂ to mating keygateway 830 and receiving corresponding mating keys 930 ₁, 930 ₂.Similar in operation, subscriber management systems 910 ₃ and 910 ₄ arecable operators, subscriber management system 910 ₅ is a directbroadcast satellite (DBS) company, and subscriber management systems 910_(K-1) and 910 _(K) are Internet content sources.

Referring to FIG. 12, a portion of a seventh exemplary embodiment of asecure content delivery system 1000 is shown. A set-top box 1010 of thesystem 1000 receives scrambled or encrypted content 1020 from a firstsource and an entitlement management message (EMM) 1040 from a secondsource. The second source may be a smart card or a CA control system.

In accordance with one embodiment of the invention, EMM 1040 comprises acopy protection key generator (CPKG) 1042 and an encrypted user key1041. As shown in FIGS. 12 and 13, encrypted user key (E_(key)) 1041 isa value that is calculated to generate a copy protection key 1035 indescrambler IC 1030 when E_(key) 1041 is decrypted by a unique key(“Unique Key”) 1031 or a derivative thereof. Unique Key 1031 is loadedduring IC manufacturer or creation of set-top box 1010. Copy protectionkey 1035 is shared with other devices, such as another set-top box 1070,a portable computer (e.g., PDA) 1071, or even a portable jukebox 1072,for decryption purposes.

As shown in FIG. 14, CPKG 1042 comprises STB manufacturer ID 1050,System ID 1051 to identify a system that provides EMM 1040 (e.g.,similar to CA Provider ID 625 of FIG. 6B) Content Provider ID 1052 toidentify the provider of the digital content (e.g., similar to ServiceProvider ID 624 of FIG. 6B), and CP Sequence Number 1053 being generallyequivalent in purpose to Mating Key Sequence Number 626 of FIG. 6B. Inaddition, CPKG 1042 includes a Copy Protection Status value 1054 thatprovides content management controls such as whether or not the incomingcontent can be copied, number of times for playback, or date/time ofplayback.

Referring back to FIG. 13, an embodiment of the descrambler IC 1030receives E_(key) 1041, CPKG 1042 and an encrypted descrambling key 1043from the second source. CPKG 1042 is substantially equivalent to matingkey generator 832 of FIG. 9A. Descrambler IC 1030 comprises a firstprocess block 1032 that decrypts E_(key) 1041 with Unique Key 1031 inaccordance with symmetric key cryptographic functions such as DES, AES,IDEA, 3DES and the like.

The decryption operation on E_(key) 1041 recovers the user key 1033,which is loaded into a second process block 1634 that is used to encryptCPKG 1042 to produce copy protection key 1035. Encrypted descramblingkey 1043 is decrypted using Unique Key 1031 (or derivative thereof) torecover the descrambling key is a clear format for descrambling and/ordecrypting the encrypted content 1020 loaded into set-top box 1010 andin particular descrambler IC 1030. Descrambling and/or decrypting mayinclude performance of 3DES operations.

As a result, the content is temporarily placed in a clear format, but isrouted to low-level encryption logic 1060, which encrypts thedescrambled content with copy protection key 1035 associated with any orall of the destination digital devices. As a result, the content issecure during subsequent transmissions.

In the foregoing description, the invention is described with referenceto specific exemplary embodiments thereof. It will, however, be evidentthat various modifications and changes may be made thereto withoutdeparting from the broader spirit and scope of the present invention asset forth in the appended claims. The specification and drawings areaccordingly to be regarded in an illustrative rather than in arestrictive sense.

1. A descrambler integrated circuit (IC) adapted to receive scrambleddigital content, a message and an encrypted descrambling key,comprising: a local memory to store a unique key; a first process blockto encrypt the message using the unique key to produce a key, the keybeing formed from a mating key generator being the message thatcomprises an identifier of a manufacturer of a digital device includingthe descrambler IC, a mating key sequence number, and an identifier of asupplier of the scrambled digital content, the supplier being one of acable provider, a satellite-based provider, a terrestrial-basedprovider, and an Internet service provider; a second process block usingthe key to decrypt the encrypted descrambling key and to recover adescrambling key; and a descrambler using the descrambling key todescramble the scrambled digital content and to produce digital contentin a clear format.
 2. The descrambler IC of claim 1, wherein the uniquekey is loaded into the local memory during manufacture of thedescrambler IC.
 3. The descrambler IC of claim 1, wherein the secondprocess block is a finite state machine.
 4. The descrambler IC of claim1, wherein the key is formed by encrypting the mating key generatorusing the unique key.
 5. The descrambler IC of claim 1, wherein themating key generator further comprises an identifier that identifies aprovider of a system that enables transmission of the scrambled digitalcontent and the mating key generator message to the descrambler IC. 6.The descrambler IC of claim 5, wherein the mating key generator furthercomprises an identifier that identifies a conditional access (CA) systemprovider over which the scrambled digital content and the mating keygenerator is transmitted.
 7. The descrambler IC of claim 1, wherein thefirst process block and the second process block are logic operating inaccordance with one of the following: Data Encryption Standard (DES),Advanced Encryption Standard (AES), and Triple DES.
 8. The descramblerIC of claim 1, wherein the unique key is a one-time programmable valuethat cannot be read or overwritten once programmed.
 9. A descramblerintegrated circuit (IC) adapted to receive scrambled digital content andto descramble the scrambled digital content, comprising: a first processblock to encrypt a message using a unique, one-time programmable key toproduce a first key, the message includes a mating key generator being amessage that comprises (i) an identifier of a manufacturer of a digitaldevice employed with the descrambler IC, (ii) a mating key sequencenumber, and (iii) an identifier of a supplier of the scrambled digitalcontent, the supplier being one of a cable provider, a satellite-basedprovider, a terrestrial-based provider, and an Internet serviceprovider; a second process block to receive an encrypted second key and,using the first key, to decrypt the encrypted second key in order torecover the second key in a non-encrypted format, the encrypted secondkey; and a descrambler using the second key in the non-encrypted formatto descramble the scrambled digital content and to produce digitalcontent in a clear format.
 10. The descrambler IC of claim 9, whereinthe encrypted second key is an encrypted service key associated with atleast one selected tier of service.
 11. The descrambler IC of claim 9,wherein the encrypted second key is an encrypted descrambling key from asmart card in communication with the descrambler IC.
 12. The descramblerIC of claim 9, wherein the mating key generator encrypted by the firstprocess block using the unique key to produce a result being the firstkey.
 13. The descrambler IC of claim 9, wherein the encrypted second keyis the second key encrypted to a mating key being a value retrieved froma remote server using the mating key generator and a serial number of adigital device implemented with the descrambler IC.
 14. A descramblerintegrated circuit (IC) adapted to receive scrambled digital content, amessage and an encrypted descrambling key, comprising: a local memory tostore a unique key; a first process block controlled by a non-CPU basedstate machine to encrypt a message using the unique key to produce akey, the message being a mating key generator that comprises (i) amating key sequence number, (ii) an identifier of a manufacturer of adigital device employed with the descrambler IC, and (iii) an identifierof a supplier of the scrambled digital content, the supplier being oneof a cable provider, a satellite-based provider, a terrestrial-basedprovider, and an Internet service provider; a second process blockcontrolled by a non-CPU state machine using the key to decrypt theencrypted descrambling key to recover a descrambling key; and adescrambler using the descrambling key to the descramble the scrambleddigital content and to produce digital content in a clear format. 15.The descrambler IC of claim 14, wherein the unique key is loaded intothe local memory during manufacture of the descrambler IC and cannot beread or overwritten once programmed.
 16. The descrambler IC of claim 14,wherein the first process block and the second process block are logicoperating in accordance with one of the following: Data EncryptionStandard (DES), Advanced Encryption Standard (AES), and Triple DES.